// @(#)RNG.java   7/2003
// Copyright (c) 1998-2003, Distributed Real-time Computing Lab (DRCL) 
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package drcl.comp.lib;

import drcl.comp.*;
import drcl.data.*;
import drcl.util.random.RandomNumberGenerator;

/**
 * A random number generation component.
 */
public class RNG extends Component implements ActiveComponent
{
  RandomNumberGenerator rng = null;
  double delay = 0.0;
  long seed;
  int ttl = -1;
  int TTL = -1;
  Port out = addPort("out", false);
  
  public RNG()
  { super(); }

  public RNG(String id_)
  { super(id_); }

  public void reset()
  {
    super.reset();
    rng.setSeed(seed);
    ttl = TTL;
  }
  
  public void duplicate(Object source_)
  {
    super.duplicate(source_);
    RNG that_ = (RNG) source_;
    seed = that_.seed;
    delay = that_.delay;
    if (that_.rng != null) 
      rng = (RandomNumberGenerator)that_.rng.clone();
  }

  public String info()
  {
    if (rng == null)
      return "delay=" + delay + ", TTL=" + ttl + "\n";
    else
      return  rng.oneline() + ", delay=" + delay + ", TTL=" + ttl + "\n";
  }
  
  protected void _start()
  {
    process(null, null);
  }

  public synchronized void _resume()
  {
    if (ttl != 0)
      process(null, null);
  }

  protected void process(Object data_, Port inPort_)
  {
    if (isStopped()) return;
    if (ttl != 0) {
      if (rng != null)
        out.doSending(new Double(rng.nextDouble()));
      if (ttl > 0) ttl--;
      if (ttl != 0) fork(out, null, delay);
    }
  }

  public long getSeed()
  { return seed; }

  public void setSeed(long seed_)
  { seed = seed_; }

  public double getDelay()
  { return delay; }

  public void setDelay(double d)
  { delay = d; }

  public int getTTL()
  { return TTL; }

  /** Sets the time-to-live value; -1 to generate numbers forever. */
  public void setTTL(int ttl_)
  { ttl = TTL = ttl_; }

  public RandomNumberGenerator getRNG()
  { return rng; }

  public void setRNG(RandomNumberGenerator rng_)
  { rng = rng_; }
}
